Field of the Invention
The present disclosure generally relates to an electrophotographic type image forming apparatus such as a copy machine and a printer.
Description of the Related Art
Electrophotographic type image forming apparatuses generally adopt methods in which voltage having opposite polarity to toners is applied to transfer members arranged to face image bearing members, thus toner images borne on the image bearing members are electrostatically transferred onto transfer materials such as sheets and overhead projector (OHP) sheets, and subsequently, fixing units fix the toner images to the transfer materials by heat and pressure.
The transfer material is sequentially conveyed from a sheet feeding cassette, a transfer unit, and the fixing unit by a conveyance roller and a conveyance belt and maintained in an appropriate conveyance orientation by a conveyance guide and a skew correction member arranged on a conveyance path. Members such as the conveyance roller, the conveyance belt, the conveyance guide, and the skew correction member are slide members slid with the transfer material when the transfer material is conveyed. When the slide members are arranged without grounding, there is a risk that the slide members are excessively charged by being slid with the transfer material and cause discharging. On the other hand, when the slide members are grounded, there is a risk that when resistance of the transfer material is lowered by moisture absorption in a high-humidity environment and the like, a transfer current is leaked from the transfer unit to the slide member via the transfer material and transfer defect may occur.
Japanese Patent Application Laid-Open No. 6-194972 describes a configuration which includes a switch circuit for switching grounding and non-grounding of a slide member slid with a transfer material and switches grounding and non-grounding of the slide member by switching ON/OFF of the switch based on an instruction from a control unit, such as a central processing unit (CPU).
However, the configuration described in Japanese Patent Application Laid-Open No. 6-194972 performs control to switch ON/OFF of the switch by providing the switch circuit, so that there is a risk of complicating the configuration of the image forming apparatus.